Silicon carrier optoelectronic packaging

ABSTRACT

An optoelectronic (OE) package or system and method for fabrication is disclosed which includes a silicon layer with wiring. The silicon layer has an optical via for allowing light to pass therethrough. An optical coupling layer is bonded to the silicon layer, and the optical coupling layer includes a plurality of microlenses for focusing and or collimating the light through the optical via. A plurality of OE elements are coupled to the silicon layer and electrically communicating with the wiring. At least one of the OE elements positioned in optical alignment with the optical via for receiving the light. A carrier is interposed between electrical interconnect elements. The carrier is positioned between the wiring of the silicon layer and a circuit board and the carrier is electrically connecting first interconnect elements connected to the wiring of the silicon layer and second interconnect elements connected to the circuit board.

CROSS REFERENCE TO RELATED APPLICATION

This application is related to the following commonly-owned, co-pendingUnited States patent application filed on even date herewith, the entirecontents and disclosure of which is expressly incorporated by referenceherein in its entirety: U.S. patent application Ser. No. (24252), for“3D OPTOELECTRONIC PACKAGING”.

BACKGROUND

The present invention relates generally to the field of integratedcircuits and silicon chip technology, and more particularly, relates toa packaging system or packaging assembly and method thereof foroptoelectronic devices in integrated circuits and silicon chiptechnology.

Computer system performance is increasingly important in currentcomputer systems and data centers, including for example, personalcomputers, servers and server farms. Computer performance is measuredby, for example, system availability, speed of computation, processorspeed, among other measurable aspects. The communication bandwidthbetween computers and within a computer is important in a computersystem's overall performance. The current trend towards multi-coreprocessors and multiple processors per machine requires an increase incommunication between processors, and between a processor and itsmemory. Current use of electrical data links perform best over shortdistances, but they reach a performance limit as the link distance andfrequency increases. Optical data links over fiber are capable of highspeed communication with low loss over large distances, however, currentoptical transceivers are bulky and expensive compared with theirelectrical counterparts.

Therefore, there is a need for a system or assembly/package and a methodfor reducing the size of optical transceivers used in computers,integrated circuits and chips. It would also be desirable for a systemor assembly/package and method to lower the cost of using opticaltransceivers in computers, integrated circuits and chips.

BRIEF SUMMARY

In an aspect of the present invention, an optoelectronic (OE) assemblyfor a semiconductor or computer chip includes a silicon layer withwiring, the silicon layer defines at least one optical via for allowinglight to pass therethrough. An optical coupling layer is bonded to thesilicon layer. The optical coupling layer includes a plurality ofmicrolenses for focusing and or collimating the light through theoptical via. A plurality of OE elements are coupled to the silicon layerand electrically communicating with the wiring. At least one of the OEelements is positioned in optical alignment with the optical via forreceiving the light. In a related aspect, the plurality of OE elementsare attached beneath the silicon layer and electrically communicatingwith the wiring, and the OE elements are positioned in optical alignmentwith the optical via for receiving the light. The assembly may furtherinclude VCSELs (vertical cavity surface emitting lasers) and photodiodesas OE elements, and interconnect elements for attaching the assembly toan additional level of packaging. The interconnect elements may includeC4s, and compressions bond pads. Further, at least one of the OEelements may be a laser diode driver and transimpedance (LDD/TIA)element, the LDD/TIA element includes circuitry, and the wiring ispositioned between the LDD/TIA element and the microlenses forelectrically connecting the LDD/TIA element to interconnect elements. Inanother related aspect, the assembly may further include a carrier forinterposing between electrical interconnect elements. The carrier ispositioned between the wiring of the silicon layer and a circuit board,and the carrier electrically connects first interconnect elementsconnected to the wiring of the silicon layer and second interconnectelements connected to the circuit board. Additionally, in a relatedaspect, the carrier may include a recessed portion for housing the OEelements. The carrier may be positioned between the wiring of thesilicon layer and a circuit board and electrically connecting firstinterconnect elements connected to the wiring of the silicon layer andsecond interconnect elements connected to the circuit board. In anotherrelated aspect, a carrier and thermal sink interposer may be positionedover the OE elements and in thermal contact with the OE elements. In afurther related aspect, a carrier and thermal sink interposer may bepositioned over the OE elements and in thermal contact with the OEelements, and the carrier may include an alignment feature forpositioning the carrier in mating relation with the optical couplinglayer. In another related aspect, at least one semiconductor element maybe attached to a carrier, and the carrier is electrically connected tothe wiring of the silicon layer and a circuit board. In another relatedaspect, the semiconductor element is selected from a group comprising: aprocessor and an application specific integrated circuit (ASIC) chip. Ina relate aspect, the assembly of claim 1 further includes at least oneadditional silicon layer including active devices connected to thewiring of the silicon layer and a carrier, the carrier electricallyconnected to the wiring of the silicon layer and a circuit board.

In another aspect of the invention, an optoelectronic (OE) package orsystem for semiconductor fabrication includes a silicon layer withwiring. The silicon layer defines at least one optical via for allowinglight to pass therethrough. An optical coupling layer is bonded to thesilicon layer, and the optical coupling layer includes a plurality ofmicrolenses for focusing and or collimating the light through theoptical via. A plurality of OE elements are coupled to the silicon layerand electrically communicating with the wiring. At least one of the OEelements is positioned in optical alignment with the optical via forreceiving the light. A carrier interposes between electricalinterconnect elements. The carrier is positioned between the wiring ofthe silicon layer and a circuit board, and the carrier is electricallyconnecting first interconnect elements connected to the wiring of thesilicon layer and second interconnect elements connected to the circuitboard. In a related aspect, at least one of the OE elements is a laserdiode driver and transimpedance (LDD/TIA) element. The LDD/TIA elementincludes circuitry, and the wiring is positioned between the LDD/TIAelement and the microlenses for electrically connecting the LDD/TIAelement to interconnect elements. In a related aspect, the carrierincludes a recessed portion for housing the OE elements. The assemblymay also include a thermal sink interposer positioned over the OEelements and in thermal contact with the OE elements. In a relatedaspect, the assembly may further include a thermal sink interposerpositioned over the OE elements and in thermal contact with the OEelements. The carrier includes an alignment feature for positioning thecarrier in mating relation with the optical coupling layer. The assemblymay further comprise at least one additional silicon layer includingactive devices connected to the wiring of the silicon layer and thecarrier.

In another aspect of the invention, a method for assembling or packaginga semiconductor or chip includes: fabricating a silicon layer withwiring, the silicon layer defining at least one optical via for allowinglight to pass therethrough; bonding an optical coupling layer to thesilicon layer, the optical coupling layer including a plurality ofmicrolenses for focusing and or collimating the light through theoptical via; coupling a plurality of OE elements to the silicon layerand the OE elements electrically communicating with the wiring;positioning at least one of the OE elements in optical alignment withthe optical via for receiving the light; and interposing a carrierbetween electrical interconnect elements, and positioning the carrierbetween the wiring of the silicon layer and a circuit board andelectrically connecting first interconnect elements to the wiring of thesilicon layer and second interconnect elements to the circuit board. Themethod may further include positioning a thermal sink interposer overthe OE elements and in thermal contact with the OE elements. In arelated aspect, the method may further include connecting at least oneadditional silicon layer including active devices connected to thewiring of the silicon layer and the carrier.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

These and other objects, features and advantages of the presentinvention will become apparent from the following detailed descriptionof illustrative embodiments thereof, which is to be read in connectionwith the accompanying drawings. The various features of the drawings arenot to scale as the illustrations are for clarity in facilitating oneskilled in the art in understanding the invention in conjunction withthe detailed description. In the drawings:

FIG. 1 is a side elevational cross-sectional view of an integratedoptoelectric (OE) assembly, including a silicon carrier, OE LDDdrivers/TIAs, OE arrays, and optical coupling elements;

FIG. 2 a is a plan view of the integrated OE assembly shown in FIG. 1;

FIG. 2 b is a bottom view of the OE assembly shown in FIG. 1 showing anoutline of LDD/TIA chip positions;

FIG. 2 c is a shows detail view of the wiring between an OE sourceregion and the OE's interconnect pads;

FIG. 3 is a side elevational view of the OE assembly shown in FIG. 1attached to a chip carrier and the chip carrier attached to a printedcircuit board using a BGA or LGA interconnect;

FIG. 4 is a side elevational view of another embodiment of an integratedOE assembly attached to a carrier, driver/TIA circuits are shownattached on the top of the carrier adjacent to the OE assembly;

FIG. 5 is a side elevational view of another embodiment of an integratedOE assembly attached to a carrier substrate, a processor or ASIC chip isadjacent to the OE assembly;

FIG. 6 is a side elevational view of another embodiment of an OEassembly attached to a carrier substrate, the light is orientateddownward and the OE devices and the divers/TIAs are cooled from the top;

FIGS. 7 a, 7 b, and 7 c are side elevational views of embodiments of OEassemblies attached to a carrier and a mating optical connector;

FIG. 8 is a side elevational view of another embodiment of an OEassembly, the silicon carrier contains through silicon vias;

FIG. 9 is a side elevational view of an alternative embodiment of an OEassembly with through silicon vias attached to a carrier substrate;

FIG. 10 is a side elevational view of an alternative embodiment of anintegrated OE assembly including a silicon carrier, OE drivers/TIAs, OEdevices, optical coupling elements, a silicon spacer frame with throughvias, and a heat spreader/alignment frame;

FIG. 11 is a side elevational view of another embodiment of anintegrated OE assembly where the drivers and TIAs have been incorporatedinto the central silicon substrate;

FIG. 12 is a side elevational view of another embodiment of anintegrated OE assembly with heat spreader and alignment frame attachedto a carrier substrate; and

FIG. 13 is a side elevational view of another embodiment of anintegrated OE assembly with a silicon spacer frame attached to a carriersubstrate.

DETAILED DESCRIPTION

In an illustrative embodiment of the present invention, referring toFIG. 1, an integrated optoelectric (OE) package or assembly 10 isdepicted and may be fabricated using standard complementarymetal-oxide-semiconductor (CMOS) processes. The OE assembly 10 includesa silicon substrate 14 that contains wiring layers 18 of fine wiringand, in an alternative embodiment, electrical circuitry. The fine wiring18 interconnects OE arrays 22 which in the embodiment of FIG. 1 is anarray of vertical cavity surface emitting lasers (VCSEL) or photo diode(PD) arrays, herein collectively referred to as the OE arrays 22. The OEarrays 22 communicate with laser diode drivers (LDD) and transimpedanceamplifiers (TIAs) collectively referred to with reference numeral 26.Dedicated wiring of the fine wiring 18 route signals from the LDDs andTIAs 26 to pads 30 have C4 bumps 34 or other interconnect elements.

A through hole 40 (or optical via) is fabricated in the substrate. Thehole 40 enables light 42 to pass from the OE device to a microlens array44 on the substrate 14. The through hole 40 is, for example, 50 to 200microns in diameter, however smaller or larger hole sizes are possibleand may be fabricated using an etch process such as, Bosch™® etch. As analternative to individual holes (one hole/OE source or detector region),a through slot which spans all OE source/detector regions of aparticular OE array may be fabricated. The microlens array 44 functionsto collimate or focus the light to and from the OE arrays 22. The glassmicrolens array 44 wafer may have a thickness of 100 to 1000 microns

In the embodiment of the present invention depicted in FIG. 1, a methodfor manufacturing the integrated optoelectric (OE) package or assembly10 includes the steps below (which are not shown in the drawings). Aftersilicon wiring layers (resulting in wiring layers 18 in the substrate14) have been fabricated on a silicon wafer, a through hole (or opticalvia) is fabricated (shown as hole 40 on the substrate 14). The hole 40enables light to pass from the OE device to a microlens array (shown aslens array 44 on the substrate 14). The through hole 40 is for example,50 to 200 microns in diameter however smaller and larger sizes arepossible and may be fabricated using an etch process such as, Bosch™®etch. The silicon wafer is then attached to a temporary handling wafer,and is ground and polished to a thickness of between about 10 to 200microns. After polishing, the silicon wafer may be further thinned bychemical etch (for example, using Si anisotropic etching, for example,TMAH (tetramethylammonium hydroxide) or KOH (potassium hydroxide)etching), leaving the Si wiring and Si circuitry on the glass handler.When the Si wiring is left on the glass, the high speed electricalperformance of the wiring is improved. Also, by leaving the Si wiringand circuitry on the glass handler, there is no need to fabricate theoptical via or optical window since all bulk Si (other than the wiringand circuitry) is removed. The silicon wafer is then transferred andattached to a glass wafer which contains microlenses. The glass wafercould contain microlenses of spherical or aspherical shapes. Themicrolenses could be refractive or diffractive or a combination. Insteadof glass other optically transparent materials could be used such as InPor GaAs (indium phosphorus or gallium arsenide), or transparent plastic.A microlens array functions to collimate or focus the light to and fromOE elements (OE arrays 22). The temporary handling wafer is then removedexposing the silicon wiring and pads. The wafer may then be bumped byattaching C4 balls (shown as solder balls 34 on the substrate 14), orother interconnect elements (for example, pins, or columns) may beattached, resulting in the silicon substrate 14. The next step in thefabrication process is to attach OE devices to the substrate 14. A VCSELarray (vertical cavity surface emitting laser diode array) or a PD array(photodiode array) is bonded to the silicon substrate using standardflip chip bonding tools (such as SUSS® Microtech flip chip bonder). TheOE to silicon chip join may consist of micro C4s solder balls,compression bonds, or other interconnects. The LDD, TIA, and the OE maybe underfilled to protect and secure the chip joins to complete thefabrication of the OE assembly 10. Other processing/manufacturingsequences of the above individual steps may be used to generate the OEassembly 10 which are within the scope and spirit of the presentinvention.

The silicon wafer may be fabricated using standard CMOS processes.Alternatively other device substrates could be used such as SiGe, GaAs,or silicon on insulator (SOI). The bonding of the glass lens wafer tothe silicon is performed using standard wafer to wafer bonding tools. Analignment accuracy of +/−1 micron is obtained.

Referring to FIG. 2 a, the OE assembly 10 includes a 2×12 array ofmicrolenses. It is understood that other lens arrangements are possible,such as a 1×12 array, a 4×12 array or larger two dimensional arrays oflenses.

FIG. 2 b shows a bottom view of the OE assembly 10 with the LDD/TIAelements 26 removed. The interconnect pads 30 are bumped with C4 balls34 as shown in FIG. 1. The interconnect pads 30 provide the connectionbetween the OE assembly 10 and a next level of packaging. High densitywiring 18 connects the pads to the LDDs and TIAs chips 48. The LDD andTIAs chips 48 are connected to pads 30 on which the OE device 10 ismounted. The through hole optical via 40 allows light to pass to themicrolenses 44. Alternatively, it may be desirable, in view of highfrequency electrical signal integrity, to control the electricalimpedance and balance the timing skew between different channels betweenthe pads 30 of the circuitry on the LDD or TIA chip 48(input/interconnect pads), and the pads 30 connecting the OE 10 toanother device (OE ouput pads). One way to control the electricalimpedance and balance the trimming skew is by minimizing the electricalsignal lines length difference between the channels in a layout circuitwiring. Another optimization includes minimizing the area of the LDD andTIA circuitry layout on the chip 48, which may involve placing theindividual LDD/TIA channel circuitry on the same pitch as the OE pads 30or OE diodes.

Referring to FIG. 2 c, a VCSEL array 22 is shown having the OE 10 with asource region 52 which emits light. The pads 30 interconnect the sourceregion 52 to silicon drive circuitry. The arrangement of pads may besimilar for the photodiode (PD) arrays 22. It is understood that the OElens array 44 (and OE devices) may be multidimensional, for example a2×12, 4×12 or a larger array of active elements.

Referring to FIG. 3, in another embodiment of the invention, a package70 includes the OE assembly 10 mounted on a carrier 60. The carrier 60may be, for example, an organic laminate, ceramic, Silicon, or othersubstrate material. The device drivers, i.e., the LDD drivers/TIA and OEarrays 22, on the OE assembly 10 protrude into a cavity 64 on thecarrier 60. C4 balls 34 interconnect the OE assembly 10 to the carrier60. The C4 interconnects 34 may be underfilled to strengthen and protectthe integrity of the join. A heat spreader 68 is positioned at thebottom of the cavity 64. The heat spreader 68 may be used to transferheat from the OE 10 and for example, CMOS devices, to the side of thepackage 70 for removal by, for example, an air cooled heat sink, a watercooled heat sink, or by other standard heat removal means. The carrier60 may be further attached to a printed circuit board (PCB) 72 by meansof a ball grid array (BGA) or land grid array (LGA) interconnect 76. Thecarrier 60 also serves as an electrical and mechanical interposer. TheOE assembly 10 is used to form a custom number of optical channels, withthe carrier 60 serving as an electrical and mechanical interposerbetween the OE assembly 10 and the PCB 72.

Referring to FIG. 4, another embodiment of the invention includes apackage 80 including an embodiment of an OE assembly 100 whereinfeatures consistent with the OE assembly 10 shown in FIG. 1 have thesame reference numerals. The OE assembly 100 includes the siliconsubstrate 14, OE arrays 22, and an attached lens array 44. In this casethe LDD and TIA devices 26 are attached to the carrier 60. It isunderstood the carrier may be organic, ceramic, silicon, or othersuitable material. It is understood that a number of OE arrays 22 may beextended beyond two arrays. It is also understood that a combinationVCSEL and photodiode arrays 22 may be used on the OE assembly 100 toprovide a transceiver function.

Referring to FIG. 5, in another embodiment of the invention, a package90 includes the OE assembly 10 (shown in FIGS. 1 and 3) and anadditional device attached to the carrier substrate 60. The additionaldevice may be a processor or ASIC (application specific integratedcircuit) chip 78, or another component. In some cases, it is highlydesirable to place the additional device 78 as close as possible to theOE assembly 10 to minimize the electrical power and cost byincorporating some or all of the LDD circuitry 26 within the additionaldevice 78. In alternative cases, it may be desirable to use standard(non-custom) additional device(s) where the needed LDD/TIA 26 circuitryrequirements are in the OE assembly 10.

Referring to FIG. 6, another embodiment of a package 120 includes the OEassembly 10 rotated one hundred and eighty degrees and attached to acarrier substrate 104. In the embodiment of FIG. 6, the carriersubstrate includes an optional recessed region, including an electricalinterconnection in the recessed region to connect the OE assembly to thecarrier 104. Alternatively (not shown), the carrier could have only ahole or rectangular opening and no recessed region, in this case,electrical interconnect is done on the bottom side of the carrier. Also,an additional interposer (not shown) could be used to create a largergap between the PCB and the OE assembly.

The light 42 is orientated downward towards the printed circuit board(PCB) 72. Optical waveguides 106 are attached to the top surface of thePCB 72. A lens array 112 is positioned on top of the waveguides 106which couples the light from the OE assembly 10 to the waveguide cores.Also, waveguide turning mirrors 108 reflect the light 42 ninety degrees.The light 42 within the optical waveguides 106 may be conveyed acrossthe PCB 72 to other optical assemblies or to an edge of the printedcircuit board for interconnection with an optical backplane or opticalfiber cables. A heat spreader 116 in positioned on the top of thecarrier 104. The thermal interface material 69 is used to connect theheat spreader 116 to the LDDs/TIAs 22, and OE arrays 22. The heatspreader 116 may be connected to a top side heat sink to remove heatfrom the package 120.

Referring to FIGS. 7 a, 7 b, and 7 c, the OE assembly 10 is attached tothe carrier 60 and a mating waveguide/optical connector 124. Referringto FIG. 7 a, an optical cable 126 is connected to the waveguide/opticalconnector 124. The waveguide cable 126 may be a polymer and incorporatesturning mirror elements 128, a lens array 44, and a connector housing132.

Referring to FIG. 7 b, an OE assembly 130 on the carrier 60 incorporatesan alignment frame 134. The alignment frame 134 is passively aligned tothe lens OE assembly 130 lens array 144, and then glued into place.During fabrication of the lens array 144, additional features may beformed which can be used to accurately position the alignment frame 134.For example, a step 136 is formed in the lens array 144, for thealignment frame 134 to reference. Thereby, after assembly the alignmentframe 134 is accurately referenced to the lens array 144 and the devices26 to specified semiconductor tool tolerances, such as, within a 1 or 2micron alignment tolerance. The OE assembly 130 is mated to the opticalconnector 124 as shown in FIG. 7 c forming a package 140. The opticalconnector 124 seals the optical elements, i.e., the turning mirrors 128,the waveguide cable 126 and connector 132 from dust or othercontaminates.

Referring to FIG. 8, an alternate OE assembly 150 according to theinvention includes wiring or circuitry 18 on top of the siliconsubstrate 14 interconnecting the VCSEL/PDs 22, and LDD/TIA 26 devices.The lens array 44 is aligned and attached to the silicon substrate orcarrier 14. The silicon substrate/carrier 14 contains through siliconvias 152 which connect the top side wiring 14 to bottom side pads 30. C4bumps 34 are attached to the pads 30. A stiffener frame 154 and a heatspreader 156 are positioned on top of one another. The head spreader 156conducts heat from the LDD/TIA 26, and PDs 22 and spreads it laterally.A conventional heat sink may be attached to the top to cool the assembly150.

Referring to FIG. 9, where like features have the same referencenumerals as the embodiments of the invention shown in FIGS. 1, 3-8,another embodiment of an OE package 160 includes through silicon vias152 in the embodiment of the OE assembly 150 shown in FIG. 8. The OEassembly 150 is attached to a carrier substrate 162. In the OE package160, shown in FIG. 9, the light 42 is directed downward towards the PCB72.

Referring to FIG. 10, where like features have the same referencenumerals as the embodiments of the invention shown in FIGS. 1, 3-9,another embodiment of an OE package 170 includes the LDDs/TIAs 26, andOE arrays 22 a are attached to a first silicon substrate/carrier 174 awhich is thicker (e.g., between 100 to 800 microns thick) than in theprevious embodiments shown in FIGS. 3-6. An optical coupling glass waferis reversed and the microlens 176 surface faces the OE arrays 22. Theglass lens array 176 may be thicker than in previous embodiments, sincethe light 42 passes through the glass substrate 176 in a collimatedmanner. A second silicon substrate 174 b includes wiring 18 and throughsilicon vias 152 as shown in FIGS. 8 and 9. The second silicon substrate174 b is used to redistribute the signals from fine interconnect pads onthe first silicon substrate 174 a to larger pads 30 (and larger pitch)on the second silicon substrate 174 b. Further, the second siliconsubstrate 174 b conducts heat from the first silicon substrate 174 alaterally to a heat spreader/alignment frame 172. The heatspreader/alignment frame 172 is bonded to the second silicon substrate174 b. A heat sink may be attached to the heat spreader/alignment frame172 to cool the OE assembly 180. The heat spreader/alignment frame 172may also serve as an alignment frame for mating with an opticalconnector. The components on the OE assembly 180 may be underfilled orsealed 178 as shown in FIG. 10. The sealing 178 serves to strengthen thecomponents and protect the internal bond pads from the environment.

Referring to FIG. 11, another embodiment of an OE assembly 200 in an OEpackage 210 is similar to the embodiment shown in FIG. 10, however, theOE assembly 200 includes LDD and TIA circuitry imbedded in the firstsilicon substrate 174 a. In some cases, it is desirable to place the LDDand TIA devices as close as possible to the OE devices 22 to minimizethe electrical power and cost by incorporating the circuitry in thefirst silicon substrate 174 a. In an alternative embodiment, the LDD/TIAcircuitry is attached to the first silicon substrate. Other embodimentsmay also include OE devices being two dimensional, e.g., containing 2×12arrays, 4×12 arrays or more devices per OE substrate.

FIG. 12 shows an OE assembly 220 of an OE package 230 with a thickersilicon substrate 224. A lens array 232 is shortened in comparison toprevious embodiments, thereby exposing a top portion of the siliconsubstrate 224. The exposed top portion of the silicon substrate 224enables a heat spreader 234 to be directly attached to the top of thesilicon substrate 224, and to be referenced laterally by referencefeatures 233 in the lens array 232. By attaching the heat spreader 234to the top of the silicon substrate 224, heat may be conducted away fromactive devices, for example, OE arrays 22 and drivers/TIAs 26, anddistributed to a top side heat sink/spreader 234.

Referring to FIG. 13, another embodiment of an OE package 240 includesthe OE assembly shown in FIG. 12, however, in the OE package 240, asecond silicon spacer 242 (or silicon frame) having silicon vias therethrough is attached to the first silicon substrate 224. In this case acavity is not required in the organic or ceramic carrier and the OEassembly may be attached to a flat carrier as shown.

Thereby, the OE packages and OE assemblies shown in the embodiments ofthe invention, integrate the OE transceiver elements in a compact space.Thereby, the present invention provides a system and assembly ofintegrated packaging, and a method of integrated packaging for reducingthe size and lowering the cost of optical transceivers. Morespecifically, the optoelectronic drivers and receivers are processed andpackaged with optical coupling elements, and OE (VCSEL and PD) elementsusing a wafer scale packaging technology, together with 3D stacking, forintegrating the elements in a compact space, resulting in improveddensity of components and lower cost manufacturing or fabrication.

While the present invention has been particularly shown and describedwith respect to preferred embodiments thereof, it will be understood bythose skilled in the art that changes in forms and details may be madewithout departing from the spirit and scope of the present application.It is therefore intended that the present invention not be limited tothe exact forms and details described and illustrated herein, but fallswithin the scope of the appended claims.

1. An optoelectronic (OE) assembly for a semiconductor or computer chip,comprising: a silicon layer with wiring, the silicon layer defining atleast one optical via for allowing light to pass therethrough from alight source; an optical coupling layer bonded to the silicon layer, theoptical coupling layer including a plurality of microlenses for focusingand or collimating the light through the optical via; a plurality of OEelements coupled to the silicon layer and electrically communicatingwith the wiring, at least one of the OE elements positioned in opticalalignment with the optical via for receiving the light, the siliconlayer and the wiring being between the OE elements and the opticalcoupling layer, and the OE elements being in spaced relation with theoptical coupling layer having the wiring therebetween; a carrier forinterposing between electrical interconnect elements, the carrierincluding a recessed portion which houses the OE elements, the carrierbeing positioned between the wiring of the silicon layer and a circuitboard and electrically connecting first interconnect elements connectedto the wiring of the silicon layer and second interconnect elementsconnected to the circuit board; and a heat spreader positioned between abottom surface of the recessed portion and a bottom surface of the OEelements, the heat spreader being configured to provide thermalconductivity from the OE elements.
 2. The assembly of claim 1, whereinthe plurality of OE elements are attached beneath the silicon layer andelectrically communicating with the wiring, and the OE elements arepositioned in optical alignment with the optical via for receiving thelight.
 3. The assembly of claim 1, further comprising: VCSELs (verticalcavity surface emitting lasers) and photodiodes as OE elements.
 4. Theassembly of claim 1, further comprising: interconnect elements forattaching the assembly to an additional level of packaging.
 5. Theassembly of claim 4, wherein the interconnect elements include C4s, andcompressions bond pads.
 6. The assembly of claim 1, wherein at least oneof the OE elements is a laser diode driver and transimpedance (LDD/TIA)element, the LDD/TIA element includes circuitry, and the wiring ispositioned between the LDD/TIA element and the microlenses forelectrically connecting the LDD/TIA element to interconnect elements. 7.The OE assembly of claim 1, further comprising: at least onesemiconductor element attached to a carrier, the carrier electricallyconnected to the wiring of the silicon layer and a circuit board.
 8. TheOE assembly of claim 7, wherein the semiconductor element is selectedfrom a group comprising: a processor and an application specificintegrated circuit (ASIC) chip.
 9. An optoelectronic (OE) package orsystem for semiconductor fabrication, comprising: a silicon layer withwiring, the silicon layer defining at least one optical via for allowinglight to pass therethrough; an optical coupling layer bonded to thesilicon layer, the optical coupling layer including a plurality ofmicrolenses for focusing and or collimating the light through theoptical via; a plurality of OE elements coupled to the silicon layer andelectrically communicating with the wiring, at least one of the OEelements positioned in optical alignment with the optical via forreceiving the light; a carrier for interposing between electricalinterconnect elements, the carrier including a recessed portion whichhouses the OE elements, the carrier positioned between the wiring of thesilicon layer and a circuit board and the carrier electricallyconnecting first interconnect elements connected to the wiring of thesilicon layer and second interconnect elements connected to the circuitboard, the silicon layer and the wiring being between the OE elementsand the optical coupling layer, and the OE elements being in spacedrelation with the optical coupling layer having the wiring therebetween;and a heat spreader positioned between a bottom surface of the recessedportion and a bottom surface of the OE elements, the heat spreader beingconfigured to provide thermal conductivity from the OE elements.
 10. Theassembly of claim 9, wherein at least one of the OE elements is a laserdiode driver and transimpedance (LDD/TIA) element, the LDD/TIA elementincludes circuitry, and the wiring is positioned between the LDD/TIAelement and the microlenses for electrically connecting the LDD/TIAelement to interconnect elements.
 11. The assembly of claim 9, whereinthe carrier includes a recessed portion for housing the OE elements. 12.A method for assembling or packaging a semiconductor or chip,comprising: fabricating a silicon layer with wiring, the silicon layerdefining at least one optical via for allowing light to passtherethrough; bonding an optical coupling layer to the silicon layer,the optical coupling layer including a plurality of microlenses forfocusing and or collimating the light through the optical via; couplinga plurality of OE elements to the silicon layer and the OE elementselectrically communicating with the wiring; positioning at least one ofthe OE elements in optical alignment with the optical via for receivingthe light; interposing a carrier between electrical interconnectelements, and positioning the carrier between the wiring of the siliconlayer and a circuit board and electrically connecting first interconnectelements to the wiring of the silicon layer and second interconnectelements to the circuit board; housing the OE elements in a recessedportion of the carrier; positioning the silicon layer and the wiringbetween the OE elements and the optical coupling layer and positioningthe OE elements in spaced relation with the optical coupling layerhaving the wiring therebetween; and positioning a heat spreader betweena bottom surface of the recessed portion and a bottom surface of the OEelements, the heat spreader being configured to provide thermalconductivity from the OE elements.